Bug:NameErrorinclean_emailmethod due to undefinedUser` model

[Zazh]

There is a bug in Chapter05/bookmarks/account/forms.py (see this file) in the clean_email method. The code uses User.objects.filter(email=data).exists(), but User is not defined or imported in this file. This causes a NameError or import issues, especially if a custom user model is being used.

Current code (problematic):

def clean_email(self):
    data = self.cleaned_data['email']
    if User.objects.filter(email=data).exists():
        raise forms.ValidationError('Email already in use.')
    return data

How to fix:
Replace usage of User with get_user_model() as follows:

from django.contrib.auth import get_user_model

def clean_email(self):
    data = self.cleaned_data['email']
    User = get_user_model()
    if User.objects.filter(email=data).exists():
        raise forms.ValidationError('Email already in use.')
    return data